03 cr 250 idle runs away

[+30]

When the bike is cold no problems, after a few fast laps when the bike gets hot idle tends to "ramp up" and with the throttle chopped (totally closed) it will sound like you have it at 1/4 throttle.Almost like a bike sounds just before running out of gas.In 1st it will even chug you up hills back to the pits with the throttle closed. Also the carb likes to pee too soon when leaning the bike over. Here are the stats and things Ive tried,
float set per manual at 15mm from bottom of float to split seam between bowl and carb with carb held 3/4 upsidedown and float vlv making contact but not depressing the "tit" (tmx 38) None of the high idle happens until the bike is good and hot.Bike runs clean no smoke. Have any of you experienced this??
Bike has no motor-mods, ign is not advanced. here are the stats:

vp-U2
Idle adjustment-no help
air screw 1 1/2 out-turned in 1/2 turn no help-
throttle cable adjustment is good
Larger Pilot(slow jet)from 30-32.5 no help.
430 main
2nd clip
checked reed cage boot for leaks. Thanks for any info...

 

[mxneagle]

check the ignition side main seal for a leak. Very simple to replace.

 

[Britt Boyette]

When was the last time you lubed your throttle cable plus cleaned and greased your throttle tube? I'd start with the simple things first. If the seal is easy enough to replace then why not do that too.

 

[CR Swade]

my idle speed on my 02 was very erratic. If you set it to idle at one outside temp or cold engine, it would be a fast idle when hot or if the weather changed. Not to mention it was a very hard starter. I never could get a stable jetting setting. Literally the bike would run one way and you could shut it off, go back out and it would run differently as the day progressed.

I gave up and put on a Keihin 38mm carb and was able to get easy starts, much better low-end, consitent idle and jetting. I have heard that JD Jetting has sorted out the Mikuni, but I never tried his settings as it wasn't available when I had my 02

 

[+30]

idle trouble

Thanks for the tips, Ill check out that seal. (actually I have just replaced the throttle cable last week but the bike did this before the cable change) I did try the JD jetting kit last week, but couldnt find a setting better than stock set up, and it still runs away. I have a full gasket kit Ill give that seal a shot. Thanks!